Translation:The plant has not germinated
again: the -ja- tense should better be translated with "not yet" (bado only places emphasis on the "yet") - unfortunately there is no such tense in English. "The plant has not yet sprouted." (or germinated)
But wouldn't adding "yet" place too much emphasis on the "yet"?
"The plant has not sprouted" still allows the possibility that it will sprout next week (though adding"yet" certainly sounds more optimistic).
Presumably "-ja-" isn't always optimistic? How do you express the idea that the plant has failed to sprout (and never will)?
"Mmea haukuota (na hautaota)." The "-ku-" negative past is an opportunity past/something that did not happen (it does not include the yet and is usually used when the possibility does not reamin). Weird negative example: Our househelp's daughter had been involved in a van kidnapping and my mother asked her if she was harmed to which the answer was "She has not been harmed yet." which sounds extreme to our ears, but she used the "ja"-tense as the perpetrators were still out there, leaving the possibility...
Perhaps "mmea" in Swahili is a more loose term than "plant" in English? ;) Otherwise you could also suggest it with the report function and the mother tongue speakers will correct it if you're right! :)